﻿/*
 *  DFUtil - a utility for creating and implementing blueprints in Dwarf Fortress.
 *  
 *  Copyright (C) 2009  Katharine Gillis
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see http://www.gnu.org/licenses/.
*/

using System.Collections.Generic;

namespace DFUtil
{
    /// <summary>
    /// Describes an observable subject for use with the Observer design pattern.
    /// </summary>
    public abstract class Subject
    {
        #region Variables

        List<IObserver> _observers = new List<IObserver>();

        #endregion

        #region Subject members

        /// <summary>
        /// Notify each observer of an update.
        /// </summary>
        /// <param name="response">Response to send to each observer.</param>
        public void Notify(object response)
        {
            foreach (IObserver observer in _observers)
            {
                observer.Update(this, response);
            }
        }

        /// <summary>
        /// Add a new observer.
        /// </summary>
        /// <param name="observer">Observer to attach.</param>
        public void Attach(IObserver observer)
        {
            _observers.Add(observer);
        }

        /// <summary>
        /// Remove an observer.
        /// </summary>
        /// <param name="observer">Observer to remove.</param>
        public void Detach(IObserver observer)
        {
            _observers.Remove(observer);
        }

        #endregion
    }
}
